Energy storage system
The present invention relates to an energy storage system. An energy storage system, according to an embodiment of the present invention, relates to an energy storage system for managing power of a system and a direct current (DC) distribution network linked with the system, the energy storage system comprising: a first converter connected between the system and the DC distribution network so as to control a voltage of the DC distribution network; a second converter connected to the DC distribution network; a load connected to the second converter, and controlling the voltage by means of the second converter; a battery connected to the DC distribution network; and a third converter connected between the battery and the load, and controlling discharge of the battery.
1. An energy storage system for managing power of a power system and power of a direct current (DC) power distribution network connected to the power system, the energy storage system comprising:
a first converter connected to and disposed between the power system and the DC power distribution network and configured to control voltage of the DC power distribution network;
a second converter connected to the DC power distribution network;
a load connected to the second converter, wherein the second converter is configured to control voltage of the load;
a battery connected to the DC power distribution network; and
a third converter connected to and disposed between the battery and the load in a path separate from the DC power distribution network, and configured to control discharging of the battery.
2. The energy storage system of claim 1 , wherein the battery discharged via the third converter is transferred directly to the load.
3. The energy storage system of claim 1 , wherein the energy storage system further comprises a fourth converter connected to and disposed between the battery and the power system, wherein the fourth converter is configured to control charging and discharging of the battery.
4. The energy storage system of claim 3 , wherein each of the first and fourth converters is configured to convert voltage supplied from the power system and to charge the battery with the converted voltage.
5. The energy storage system of claim 3 , wherein the battery discharged via the third converter is transferred directly to the load,
wherein the battery discharged under control by the fourth converter is transferred to the power system.
6. The energy storage system of claim 3 , wherein the energy storage system further comprises:
an auxiliary power system connected to the load; and
a switch configured to selectively connect the fourth converter to a first node between the power system and the first converter or to a second node between the auxiliary power system and the load.
7. The energy storage system of claim 6 , wherein one end of the switch is connected to the fourth converter, while the other end of the switch is selectively connected to either the first node or the second node.
8. The energy storage system of claim 6 , wherein when the power system fails while the fourth converter is connected to the first node,
the fourth converter is connected to the second node via an switching operation of the switch,
the battery is discharged under control by the fourth converter, and
the battery is discharged to the load via the second node.
9. The energy storage system of claim 3 , wherein the first converter operates in a DC voltage control mode to control voltage of the DC power distribution network,
wherein the second converter operates in a constant voltage constant frequency (CVCF) mode to control voltage of the load,
wherein each of the third and fourth converters operates in a power control mode to control power supplied by the battery.
10. The energy storage system of claim 3 , wherein the first converter is configured to convert alternating current (AC) voltage supplied from the power system to DC voltage and supply the converted DC voltage to the DC power distribution network, or to convert DC voltage supplied from the DC power distribution network to AC voltage and supply the converted AC voltage to the power system,
wherein the second converter is configured to convert DC voltage supplied from the DC power distribution network into AC voltage and supply the converted AC voltage to the load,
wherein the third converter is configured to convert DC voltage supplied from the battery into AC voltage and supply the converted AC voltage to the load,
wherein the fourth converter is configured to convert AC voltage supplied from the power system to DC voltage and supply the converted DC voltage to the battery, or to convert DC voltage supplied from the battery to AC voltage and supply the converted AC voltage to the power system.
11. An energy storage system for managing power of a power system and power of a direct current (DC) power distribution network connected to the power system, the energy storage system comprising:
a first converter connected to and disposed between the power system and the DC power distribution network and configured to control voltage of the DC power distribution network;
a second converter connected to the DC power distribution network;
a battery connected to the second converter, wherein the second converter is configured to control charging and discharging of the battery;
a third converter connected to the DC power distribution network;
a load connected to the third converter, wherein the third converter is configured to control voltage of the load; and
a fourth converter connected to and disposed between the battery and the load in a path separate from the DC power distribution network, wherein the fourth converter is configured to control discharging of the battery.
12. The energy storage system of claim 11 , wherein voltage discharged from the battery under control by the second converter is transferred to the load via the DC power distribution network,
wherein the battery discharged via the fourth converter is transferred directly to the load.
13. The energy storage system of claim 11 , wherein the energy storage system further comprises a fifth converter connected to and disposed between the battery and the power system, wherein the fifth converter is configured to control charging and discharging of the battery.
14. The energy storage system of claim 13 , wherein the second converter is configured to convert voltage supplied from the DC power distribution network and to charge the battery with the converted voltage,
wherein the fifth converter is configured to convert voltage supplied from the power system and to charge the battery with the converted voltage.
15. The energy storage system of claim 13 , wherein voltage discharged from the battery under control by the second converter is transferred to the load via the DC power distribution network,
wherein the battery discharged via the fourth converter is transferred directly to the load,
wherein the battery discharged via the fourth converter is transferred directly to the load.
16. The energy storage system of claim 13 , wherein the energy storage system further comprises:
an auxiliary power system connected to the load; and
a switch configured to selectively connect the fifth converter to a first node between the power system and the first converter or to a second node between the auxiliary power system and the load.
17. The energy storage system of claim 16 , wherein one end of the switch is connected to the fifth converter, while the other end of the switch is selectively connected to either the first node or the second node.
18. The energy storage system of claim 16 , wherein when the power system fails while the fifth converter is connected to the first node,
the fifth converter is connected to the second node via an switching operation of the switch,
the battery is discharged under control by the fifth converter, and
the battery is discharged to the load via the second node.
19. The energy storage system of claim 13 , wherein the first converter operates in a DC voltage control mode to control voltage of the DC power distribution network,
wherein each of the second converter and the fourth and fifth converters operates in a power control mode to control power supplied by the battery,
wherein the third converter operates in a constant voltage constant frequency (CVCF) mode to control voltage of the load.
20. The energy storage system of claim 13 , wherein the first converter is configured to convert alternating current (AC) voltage supplied from the power system to DC voltage and supply the converted DC voltage to the DC power distribution network, or to convert DC voltage supplied from the DC power distribution network to AC voltage and supply the converted AC voltage to the power system,
wherein the second converter is configured to convert DC voltage supplied from the DC power distribution network into DC voltage and supply the converted DC voltage to the battery, or to convert DC voltage supplied from the battery into DC voltage and supply the converted DC voltage to the DC power distribution network,
wherein the third converter is configured to convert DC voltage supplied from the DC power distribution network into AC voltage and supply the converted AC voltage to the load,
wherein the fourth converter is configured to convert DC voltage supplied from the battery into AC voltage and supply the converted AC voltage to the load,
wherein the fifth converter is configured to convert AC voltage supplied from the power system to DC voltage and supply the converted DC voltage to the battery, or to convert DC voltage supplied from the battery to AC voltage and supply the converted AC voltage to the power system.